Electrostatic texturing process and apparatus therefor

ABSTRACT

A process and apparatus are claimed for electrostatically texturing a multistrand textile material. The textile material is given sufficient charge density to cause the strands thereof to flare and while in the flared state the strands are electrostatically attracted and driven around a closed path, imparting a flase twist thereto. Apparatus is also disclosed and claimed for a twist means including a twist chamber, a plurality of electrodes disposed about the chamber and means for generating a driving charge on the electrodes and moving same therearound. Particularly, pairs of electrodes define a closed path about the chamber and a voltage potential is created across each pair while a maximum potential is created across one pair. The flared strands are attracted by one of the maximum potential pair of electrodes and repulsed by the other and driven by sequentially moving the maximum potential from pair to pair around the path.

[451 Dec..4, 1973 [75] Inventor:

[ ELECTROSTATIC TEXTURING PROCESS AND APPARATUS THEREFOR James R. Bond, Spartanburg, S.C.

[73] Assignee: Hoechst Fibers Incorporated,

Spartanburg, S.C.

22 Filed: Mar. 27, 1972 21 Appl. No. 238,061

52 us cl ..s7/77.3, 57/34 HS, 57/157 TS 51 Int. Cl. ..D02g l/04,D0lh 7/92 [58] Field of Search ..'.....57/34 R,

Primary Examiner-Donald E. Watkins Attorney-Wellington M. Manning, Jr.

[57] ABSTRACT A process and apparatus are claimed for electrostatically te'xturing a multistrand textile material. The textile material is given sufficient charge density to cause the strands thereof to flare and while in the flared state the strands are electrostatically attracted and driven around a closed path, imparting a fiase twist thereto. Apparatus is also disclosed and claimed for a twist means including a twist chamber, a plurality of electrodes disposed about the chamber and means for generating a driving charge on the electrodes and moving same therearound. Particularly, pairs of electrodes define a closed path about the chamber and a voltage potential is created across each pair while a maximum potential is created across one pair. The flared strands are attracted by one of the maximum potential pair of electrodes and repulsed by the other and driven by sequentially moving the maximum potential from pair to pair around the path.

16 Claims, 5 Drawing Figures PATENTEU B 4 75 SHEET 1 BF 2 1 V ELECTROSTATIC TEXTURING PROCESS AND F APPARATUS THEREFOR BACKGROUND OFTHE INVENTION During the past 20 years, an enormous amount of technology has evolved in the area of texturizing synthetic fibers to produce either stretch orbulk yarns for the production of knit; goods, especially. garments. These yarns inge'neral aremultitilament, thermoplastic yarns and are normally knitted into hosiery, innerwear,

outerwear'and the likefor the apparel markets.

Numerous processeshave been developed for treatment of the yarns to impart the desired stretch or bulk characteristics thereto. These processes are ofseveral distincttypes, each ofwhich is accompanied by numerous improvements thereto. For example, a large efiort has been expended in the false twist processing of multifilament synthetic fibers where the fibers are passed around a pin located in or adjacent a rotatingspindle.

In this fashion, a false twist, which is a term well known to those skilled in the art and need notbe further discussed, is imparted to the yarn being processed. Numerousimprovements havefurther been made to improve the rotational speed of the false twist spindles, the placement of the pin with respect to the spindle, and the like so as to improve the quality of the yarn being processed and to improvethe speed at which the false twist is imparted. False twist has also been imparted to fibers by frictional engagement between the filaments and a moving or rotating body, such as twist bushings,oppositely driven belts, and thelike. Both stretch and bulk yarns can be produced by the false twist processes.

Other processes for the texturizing of synthetic yarns include the gear crimp process where the yarn is passed between meshing gears and isdistorted according to the configuration of the gear teeth to crimp the yarn. A stuffer box process involves the forcing of yarn into apparatus having a constructed area so as to physically produce convolutions in the yarn and to crimp the yarn due to the constrictions and the forces applied to the yarn. A further process involves the passing of yarn around an edge having a particular radius of curvature so as to crimp the yarn. Yarns have also been textured by knitting same into'a fabric, and after appropriate treatment, deknitting the fabric to obtain the crimped yarn. Furthermore, certain processes have been invented to chemically affect the molecular configuration of the polymer structure and thus produce a textured yarn. Yarn has also been subjected to, the action of electrostatic forces, electromagnetic forces and supersonic pulses as the yarn passes through a treatment zone.

Utilization of one of the abovementioned techniques for altering the molecular configuration of the yarn in conjunction with heat treatment of the yarn, permits the active and latent characteristics of the yarn to be controlled or changed as desired. For example, the shape, lustre, cross sectional area, torque, resilience, residual shrinkage, texture, elasticity, stretch, stretch recovery, and dimensional stability may be modified and/or controlled.

The very large majority of textured yarns being manufactured in the world today are processed according to one or more of the abovementioned systems to produce a stretch or bulk yarn depending upon the conditions of the process. Moreover, the patented prior art is replete with various andsundry modifications and improvements to the aforementioned texturing processes so as to improve the quality of the yarn being produced as well as the speed of processing, improve operating maintenance, reduce capital costs,,and the like, Each of the above processes, is, however, limited, especially with respect to processing speeds due to frictional engagement between the yarn and the apparatus for texturing same or some other physical limitation of the process conditions or apparatus employed.

The instant process and apparatus for electrostatically false twisting yarn represents .an improvement over known texturing processes and apparatus and are not burdened by the physical shortcomings of the presently existing processes and apparatus. The present process permits the false twist texturing of multifilament yarns at speedsin excess of those being realized today, without adversely effecting the degree of texturing or the qualityof textured yarn. Further, large denier yarn bundles may equally be processed according to the present invention.

There is no known prior art that in any way teaches or suggeststhe process and apparatus of the present invention. The closest known prior art is felt to be represented by U. S. Pat. Nos. 2,158,415 to Formbels; 2,442,880 to Schwartz; 2,468,826 to Kennedy et al.;

. 2,711,626 to Oglesby, Jr. et al.; 2,740,184 to Thomas;

2,855,750 to Schrenk et al.; 3,046,632 to Tsutsumi;

8,052,009 to Epstem et al.; 3,105,164 to Favrot;

3,107,478 to Arshinov et al.; 3,163,976 to Juillard; 3,268,971 to Lockwood, Jr.; 3,411,284 to Corbaz et al.; and 3,537,249to Mayer, Jr.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved electrostatic process for the texturing of multistrand textile materials.

Another object of the present invention is to provide a novel apparatus for the electrostatic texturin g of multistrand textile materials.

Still further, another object of the present invention is to provide a novel rotating alternating current electrical field for imparting false twist to a multistrand textile material.

Another object of the present invention is to provide a novel twist chamber for the false twist texturing of textile materials.

Generally speaking, the present invention relates to a method of false twist texturing a multistrand textile material comprising the steps, of imparting sufficient electrical charge density to said strands to cause said strands to flare; passing said strands under propertension conditions through a twist zone where saidstrands flare internally of the twist zone; creating a voltage potential across said twist zone to attract said flared filaments to an oppositely charged portion of said twist chamber and electrically moving-the voltage potential around a closed path defined within said twist chamber to drive said flared strands around said closed path and impart false twist to the material.

The apparatus of the present invention generally comprises a twist zone chamber having a plurality of electrodes disposed thereabout, said electrodes defining a closed path around a passageway through said twist chamber; electrical means associating one of said electrodes with another of said electrodes whereby a voltage potential can be created thereacross, said electrical means further uniting said pairs of electrodes to create-an electrical closed path therearound; voltage supply means for said electrodes; and means for creating maximum voltage potential across one pair of electrodes and shifting maximum voltage potential from one electrode pair to an adjacent electrode pair around the closed path created by said electrodes.

More specifically, while the twist zone chamber can have any desired shape or configuration, a plurality of pairs of electrodes are disposed about a yarn passageway extending through said chamber. Each pair of electrodes is provided with means for generating a voltage potential thereacross, preferably a preamplifier, an amplifier and a transformer. Further, all of the preamplifiers for the electrode pairs are electrically associated in series with an oscillator whereby direct current voltage is converted to an alternating currentvoltage. A phase shifting circuit is provided between each of the preamplifiers to shift the phase angle of the voltage by an amount determined by the components of the circuitry and according to the number of electrode pairs employed. As such, while a potential exists across each pair of electrodes, a maximum voltage potential is created at one of the pairs of electrodes which by virtue of the phase shift arrangement, is transferred from pair to pair around the closed path.

Preferably, in addition to the above arrangement, means are employed in the circuitry to equalize the amplitude of the voltage being applied to the electrodes so as to provide a constant driving force around the closed path.

The twist zone chamber is preferably enclosed according to the teachings of thepresent invention so as to reducev interference caused by viscous drag of the strands moving through air which is subject to set up air currents that could be detrimental to successful operation of the process. As such, the entrance and exit to the twist zone chamber are preferably controlled so as to limit the flow of air therethrough. Throttling orificies are suitable for this control. Additionally, in certain cases it has been found desirable to operate the twist zone chamber under reduced pressure conditions or under controlled-atmosphere conditions. The chamber is thus preferably associated with pressure control means and/or environmental control means whereby the pressure within the chamber can be reduced or whereby a particular gas may be used to flood the chamber so as to provide a desired environment for false twisting of the textile material.

Textile materials that may be processed according to thepresent invention and by the apparatus of the present invention are those materials that may be textured. Such materials include the synthetic, thermoplastic filaments and the like which inherently may be textured as well as strands of synthetic fibers and strands of natural fibers, blends of natural and synthetic fibers and the like which have been pretreated so as to become susceptible to texturization, if necessary. Moreover, the materials may be electrically insulative, semiconductive or conductive either by natural characteristics or by a finish applied thereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a line drawing of a texturing process in which the novel false twist means of the present invention may be employed.

FIG. 2 is a vertical cross sectional view of a twist DESCRIPTION OF THE PREFERRED EMBODIMENTS Textile materials that may be textured according to the present process include 'strands of all types of yarns, tows, etc. that may per se, be textured. Such materials generally include multifilament synthetic, thermoplastic yarns and strands manufactured from synthetic fibers and blends of synthetic fibers with natural fibers. Multiple strands of natural fibers that have been pretreated to accept texturization may also be processed according to the teachings of the present invention. For example, polyamides, polyesters, acrylics and the like are exemplary of the types of synthetic fibers that may be very suitably processed according to the teachings of the present invention. Such yarns should be multifilament or multistrand to produce a yarn bundle. Moreover, the process of the present invention may be utilized so as to produce a stretch yarn or a set, bulk yarn as desired.

The apparatus of the present invention is ideally suited for use in conjunction with existing process equipment or as an independent item of process equipment. For example, yarn to be processed according to the present invention may be fed from an extrusion systern directly to the texturing apparatus of the present invention. Likewise, yarn may be supplied from a package of drawn or undrawn yarn, or may be processed on a draw twister, draw winder, or the like that embodies the novel apparatus of the present invention.

Referring to the Figures, specific embodiments of the present invention will now be described in detail. In FIG. 1, there is shown an exemplary arrangement for false twist texturing of yarns. A multifilament yarn Y composed of filaments F is removed from a yarn supply source generally indicated as 10 by feed means 20 (shown as nip rolls), past a heater means 30, a cooling zone generally indicated as 35, a filament charge zone generally indicated as 40, a false twist zone generally indicated as 50, optional feed means 60, an optional heater 65 (shown in phantom), feed means and a yarn take up means generally indicated as 80.

Yarn feed means 20, 60 and 70 serve several possible functions, and may take several configurations other than the nip rolls shown in FIG. 1. For example, feed means 20 and 60 or 70 provide power for movement of a yarn through the apparatus, act as twist stops upstream and downstream respectively from twist zone 50, control tension in the yarn, and the like. Moreover, feed means 20, 60 and 70 may be heated rolls to serve as pre and post heaters for the yarn, in lieu of independent heat sources 30 and 65. Optional feed means 60 may be employed in conjunction with heater means 65 if it is desirable to produce a bulk yarn. In such an arrangement feed means 60 is utilized in conjunction with feed means to control yarn speed and tension in the twist zone and is also coordinated with feed V final characteristics of the yarn aswell known in the art. Numerous feed means are well known in. the art and the particular configuration thereof is well. within the purview of one skilled in the art. Moreover, twist stop means may be independent of the feed means if desired. Driven nip rollsare, however, preferred.

Heater means 30, and heater means-65. (shown in phantom as. being-optional) are also well :known to those skilled in atexturing art. As such, depending upon the particular situation, heatermeans and 65, if employed, may be space heaters, a heated liquid, heated godets, strip heaters, tube heaters, radio fre-' quency heaters, or the like. Heat may thus be supplied to the yarn by radiation, conduction and the like.

The yarn or strand charge zone 40 precedesand succeeds the twist zone 50..and containsan electrically conductive element 41 for applying .an electrical charge to the filaments F that make up yarn Yand a conductive element 44 for neutralizing the charged filaments after twisting. Conductiveelementwtl is operatively associated with a direct current generator 42 by a. suitable connector 43. Yarn Y passes element 41 where the individual filaments F receive an electrical charge of a certain polarity. Once filaments F receive an electrical charge at element 41, eachfilament tends to repel adjacent filaments F since theyall have the same polarity electrical charge.-As yarn tension and space permits, the filaments flare outwardly. Conductive element41 may be separate from twist zone or a part thereof as will be described in-detail hereinafter. Moreover, conductive element 41 maybe a conductive, wear resistant metal, ceramic or plastic as desired and the shape of same may be determined by the prerequisites of the particular yarn being textured. A tubular beryllium-copper or stainless steel element is preferred.

The D.C. generator 42 shouldpreferably be a variable voltage generator since the magnitude of voltage required to produce a satisfactory filament fiare' will vary with the number of filaments, the degree of conductivity of the filaments, the linear speed of yarn travel and the like. A Van de Graaff generator or the like is quite acceptable for certain purposes. A variable voltage supply with outputs of from about 5000 to about 100,000 volts is generally suitable. Second conductive element 44 is present at or adjacent the exit end of the twist zone 50 and, like element 41 is operatively associated with direct current generator .42 through a conductor 45. Conductive element 44 transmits electrical charges of opposite polarity to that of element 41 and when engaged by filaments F, neutralizes the charge thereon or conveys the charge from filaments F. Hence after the false twist is impartedthereto, the electrical charge on the yarn bundle is removed.

As mentioned earlier, depending upon the degree of conductivity of the yarn, different types of electrical charges are present. Hence conductive elements 41 and 44 will provide a different mechanism for a truly conductive yarn, by continually passing direct current therethrough. The electrical charge, though moving tion combines a driver charge generator and moving means into one electrical unit whereby no moving mewith respect to the yarn, would have sufficient chatge density to cause] the filaments to flare.

.After receiving an electrical charge of a sufficient density yarn Y next passes into. the twistzone 50. As

mentionedearlier, ambient air currents, viscousdrag of.

the filaments through thelair and the like canadversely affectthe operation of the .present process, A twist zone chamberSl is thus preferably provided in which atmospheric conditions can be controlled. Chamber,

is preferably cylindrical in shape though other geometric configurations arequire acceptable. Chamber.5l is thus also provided with a yarn entrance SZ anda yarn exit 53. Entrance 5 2and exit 53 are preferably seals or .restrictors to enable accurate controlof the atmosphere within thechamber. Further, entrance 52 rnay have integral therewith as shown in FIG. 1, conductive element 41 of charge zone, and exit 5.3 rnay have integral therewith, conductive element 44 that. ,isalso electrically connected to generator 42 by a connector 45. Element 44, .as mentioned above. neutralizes the charge on filaments F. Elements 41 and 44 are both preferably beryllium-copper or stainless steel tubular r members having flared ends thereon. Chamber 51. is manufactured of anon conductivematerial, preferably .a plasticmaterial such as a plexiglass, a polycarbonate, orthe like and has a connection 54 to which is affixed a .tubulartmember 55. Tubular member 55 is operatively associated witha control means C which maintains the proper: predetermined atmosphere within electrodes which defines a closed-path around the yarn passageway. Electrodes 56 are insulated fromeach other and operatively associatedwith a driver electrical charge generator and moving means S as will be described hereinafter. A preferred embodiment of the electrical strand twisting means ofthe present invenchanical components are present in the twist zone. Thus according to the embodiment shown in FIG. 1, a driving charge is created on at least one of the electrodes 6 a s. cha ge s sequen a y mov rom electrode to electrode to drive. the charged filaments F around the inner periphery of chamber 51.

Electrodes 56 may be arrangedaccording to the dictates of the particular end result being sought. For example, the number of electrodesrequired will be dependent upon the arrangement for generating and moving the driving electrical charge. Moreover, the size and shape of-the electrodes could likewise be varied according to the dictates of the yarn being processed, the linear speed of yarn, travel, the desired number of turns per inch and thelike. Preferably, electrodes 56 are positioned around the inside wall of chamber 5l though other positions are acceptable. It should be realized, however, that a much greater driving electrical charge will be requiredwhen the electrodes are moved away from close proximity to the filaments.

FIG. 2 illustrates yarn flare within a chamber 251 of a twist zone 250. Upon receiving an electrical charge at conductive element 241, individual filaments F of yarn Y immediately seek to repel each other. The restrictive dimension of the preferred tubular element 241 permits only limited repulsion until the yarn is within chamber 251. Once within chamber 251, the filaments' would normally balloon in all directions (not shown). When, however, the driving electrical force is generated at electrodes 256, the oppositely charged filaments move into the quadrants nearest the most powerful attractive force (See FIG. 3). The electrical charge on filaments F varies such that certain of the filaments have a greater charge density than others. The filaments having the greater charge density are thus drawn closer to the electrodes 256 and continue to repel the filaments with lesser charge density away from the electrodes 256. As such, the filaments remain in a flared condition. Also, in a preferred arrangement according to the present invention, a driving electrical charge of like polarity to that on the filaments F is present at the opposite side of the twist chamber from the attractive driving charge. The like polarity driving charge thus tends to repel filaments F into the quadrants nearest the attractive driving charge. Hence the driving charge for this preferred arrangement is a combination of repulsion and attraction of filaments F. As the driving electrical charge moves around chamber 251, the filaments having the highest charge density follow immediately while the lesser charge density filaments lag behind. Movement of the driving charge around the closed path thus drives the charged filaments F in the same path and yarn Y is twisted.

FIG. 3 illustrates a horizontal cross section of a twist zone chamber having eighteen consecutively numbered electrodes equally spaced around the inner chamber wall. A preferred means for generating and moving a driving electrical charge around the eighteen electrodes is a rotating alternating current field. The electrodes are grouped in pairs and the pairs are electrically associated with each other. Each electrode in a pair is geometrically opposite the other; A voltage potential is thus created across each pair of electrodes simultaneously with a maximum potential across only one pair. As the maximum voltage is shifted, voltage is continuously applied to the other electrode pairs in lesser amounts. At any one time therefore, a sinusoidal voltage distribution exists around the peripheral electrodes which also contributes to the electrical forceson the filaments. Hence one of the electrodes of the pair at maximum potential possesses a charge of opposite polarity to the charge on the filaments and thus attracts the filaments thereto. The other electrode of the pair simultaneously possesses a charge of like polarity to that on the filaments and repels the filaments. Likewise, like and opposite charges of different values are present on the other electrodes, the magnitudes of which are dependent upon location of the particular electrode with respect to the most positive or most negative voltage.

As the maximum voltage shifts from one electrode pair to the next, the attractive-repulsive forces cause the filaments to follow the shift and thus drive the flared filaments around the closed path of the electrodes. For example, with the electrodes 1 and 10, 2 and 11, 3 and 12, etc. being paired, and electrode 1 having a charge polarity opposite that on filaments F,

the flared filaments would assume a configuration similar to that shown in FIG. 3. Thereafter, as maximum potential is shifted around the electrode path, the bundle of flared filaments will be driven thereby. Continuous driving of the filaments about the closed path imparts twist to the yarn Y. As the driving of filaments F occurs, the opposite electrode of the pair would also continue to repel the filaments toward the attractive electrode. Moreover, the mutual repulsion among filaments continues to maintain the flared filament condition.

Sequential movement of maximum voltage potential from electrode pair to electrode pair in a clockwise direction produces an S twist in the yarn bundle upstream of the twist zone, stopping at feed rolls 20 which act as a twist stop. counterclockwise movement produces a Z twist in the yarn. Movement of the twist away from the twist zone enables the setting of the twist in the appropriate fashion as accomplished by conventional texturing techniques.

FIG. 4 is a block diagram illustrating the operation of the preferred electronics according to the present invention. A series of preamplifiers, amplifiers and transformers are connected to pairs of electrodes. Conforming to the arrangement as shown in FIG. 3, eighteen electrodes, E1 through E18 are present around the twist zone chamber thus providing nine electrode pairs. Each of the two electrodes comprising a pair is physically located on an opposite side of the chamber 51. A maximum voltage potential created across one of the pairs thus provides one of the electrodes at maximum positive voltage and the other at maximum negative voltage. Depending upon the polarity of the charge on the filaments F, one of the electrodes repels the charged filaments while the other attracts'same. While a maximum voltage potential occurs across only one pair of electrodes at any one time in the cycle, as mentioned above, there is always voltage potential across each pair of electrodes though varying in magnitude in a sinusoidal distribution. According to the arrangement of the present invention, as time progresses the maximum voltage potential is shifted from pair to pair so as to move the maximum driving force around the closed path defined by the electrodes.

According 'to the block diagram of FIG. 4, the preferred electronic arrangement of the present invention utilizes a preamplifier, amplifier and transformer for each electrode pair. A phase shift oscillator is produced by inverter preamplifier IPAl and preamplifiers PA2 through PA9. Phase shift means are provided between each two preamplifiers to create a 20 shift in voltage. In essence therefore the D.C. voltage which is applied to each preamplifier from a D.C. source, is converted into alternating current voltage at the output of each preamplifier. The last preamplifier PA9 provides input back into inverter preamplifier IPAl degrees out of phase from the output voltage of IPAl. This input voltage is then inverted by the inverter and a 0 voltage output results. Gain adjustments (See FIG. 5) are preferably provided with each preamplifier to adjust the preamp outputs to an approximately equal amplitude.

The phase shifted preamp outputs are applied to the corresponding power amplifiers A1 through A9. Corresponding transformers T1 through T9 thus receive amplified voltage of approximately constant amplitude from power amplifiers Al through A9. Transformers Tl through T9 are center tapped at the respective'secondary' windings thus rendering the two leads therefrom oppositein polarity, the leads being connected to electrode pairs El and E10, E2 and E11 and the like. Since the secondary winding leads are connected to geometrically opposite electrodes, the electrodes possess opposite charges of like voltage magnitude.

Voltage is present on all of the electrodes of the system at any one time. Likewise, however, at any one time, one pair of the electrodes will be represented by a most positive electrode and a most negative electrode while other electrodes in the system will have a less negative or less positive voltagewith constant charge in the direction of a more positive or more negative voltage. As oscillation continues, each electrode in turn will be most positive and most negative during one complete cycle of oscillation.

The sinusoidal voltage distribution thus enables the attraction-repulsion of the flared, charged filaments into the segment of the closed path adjacent the most powerful opposite voltage. Thereafter as the most powerful opposite voltage moves from electrode to electrode during the oscillation cycle, the filament bundle is driven thereby, imparting false twist to the bundle. The speed of movement around the electrode path is at least in part dependent upon the frequency of oscillation. Preferably frequency of oscillation maybe controlled by simultaneously changing the variable resistors of the resistor-capacitor phase shift networks (See FIG. 5).

Depending upon the dictates of the particular process,.the amplifiers Al through A9 or the preamplifiers IPA] through PA9 may not berequired. In fact, the basic prerequisite of the electronics is to provide a constant amplitude voltage to the transformers with the desired amount of phase shift between transformers with oscillation to convert direct current into alternating current; As mentioned above, however, the electronic arrangement of FIG. 5 is preferred.

Amplifiers A1 through A9 are thus of like value to maintain equal voltage amplitude to transformers Tl through T9. Likewise transformers T1 through T9 are of like rating. A constant driving force is thus created and maintained at the electrodes during practice of the present invention.

Each pair of electrodes is provided with its own driving unit which may comprise amplification means, preferably a preamplifier and a power amplifier, and a transformer. Each driving unit may be separate from a component standpoint though all must be electrically associated by phase shifting networks, or certain of the components may be coupled together to simplify the electronics as illustrated in FIG. 5.

As mentioned above, the number, size and shape of the electrodes employed in the electrostatic false twist means of the present invention may be varied as desired. Depending upon the number of electrodes employ ed, the phase angle difference between adjacent driving units is generally a figure equal to the number of electrodes divided into 360. This angle shift is attained by the proper selection of the resistors and capacitors comprising the phase shift circuit between the preamplifiers, amplifiers, or the like. Further, the speed of the driving force passing around the closed path within the twist zone chamber may be varied as desired. Preferably, the circuit operates at a frequency of 25,000Hz to 90,000I-Iz so as to achieve a desired number of revolutions around the closed path for successful impartation of false twist to. thetextile material at eco-- nomical line speeds.

Referring to FIG. 5, specific circuitry of the preferred embodiment of the present invention will now be described in detail. The circuitry as shown in FIG. 5 utilizes six electrodes, 501 through506, the electrodes being in pairs of 501 and 504; 502 and 505; and 503 and 506. The number of electrodes in this particular illustration is low to implement clarity of illustration of the preferred electronics for producing the rotating alternating current field. An inverter amplifier200-is shown receiving eightvolts of direct current from a source 201. Inverter amplifier 200 also receives input from the opposite end of the circuit through a connector 232. Outputfrom inverter amplifier 200 provides a voltage input to an isolation amplifier 210. Isolation amplifier 210 in turn provides input to a poweramplifier 310 which in turn supplies input toa transformer 410. Transformer 410 is connected to electrodes 501 and 504 and creates analternating voltage potential thereacross. I

Isolation amplifier 210 further provides input to a preamplifier220 through a connector 212, the input being subjected toa capacitor2l4 and variable resistor 216 so as to shift the phase angle of the voltage in accordance with the particular. arrangement. As shownin FIG. 5, a voltage shift of 60 would be experienced.

Preamplifier 220 thus receives the voltage shifted at a phase angle of 60 and provides input to power amplifier 320 which inturn provides input to a transformer 420. As with transformer 410, transformer 420 is connected to a pair of electrodes, in this case, 502 and 5 05. Output from amplifier 220provides input to amplifier 230 through a conductor 222. Conductor 222 has a capacitor 224 and a variable resistor 226 .therealong which is prearranged to shift the phase angle of the voltage by 60 at preamplifier 230. Thereafter, preamplifier 230 provides input to power amplifier 330 and amplifier 330 provides input to transformer 430 which in turn is connected to electrode pairs 503 and 506.

I Preamplifier 230 in addition to providing input to power amplifier 330, returnsthe voltage toinverter amplifier 200 through. conductor 232 where the voltage is inverted back to a phase angleof 0 thus completing the 360 circle. Attenuation in the phase shifting networks is compensated for by gain adjustments 240, 250 and 260 on the preamplifiers, providing equal ampli tude voltage into the power amplifiers.

While, ascan be seen from FIG. 5, each pair of electrodes has a separate driving circuit, it is preferable that the component parts of each driving circuit be equivalent to others in the system whereby an approximately constant voltage is applied toeach electrode pair during phase shifting around the circle so as to provide a constant driving force on the flared filaments. Hence power amplifiers 310, 320 and 330 are preferably of like value while transformers 410, 420 and 430 are I likewise preferably identical.

A better understanding of the present invention may .be had by reference to the following paragraph which ample, a drawn polyethylene terephthalate yarn (.150

denier, 32 filament) may be padded with a conductive finish such as, for example, a 20 per cent aqueous solution of the potassium salt of mono and dihexyl phosphate. The yarn may then be fed at a predetermined speed through charge zone 40 where the filaments receive an electrical charge sufficient to cause the individual filaments to flare outwardly, where tension and area permits, and into twist zone 50. Tension should be maintained in the yarn bundle at a level where the filaments flare within thetwist zone chamber 51 without making contact with the electrodes 56 around the twist chamber wall. Voltage is supplied to the electrodes which creates potential across each pair with a maximum potential across only one pair, with one of the electrodes of the pair attracting the charged filaments and the other repelling the charged filaments. The phase shifting arrangement of FIG. will shift the maximum potential from electrode pair to electrode pair, with the attracted filaments following the maximum potential around the twist chamber, imparting twist to the yarn bundle. A frequency of from 25 KHz to 90 KHz is preferred. Imparted twist will move upstream of the twist zone and be set according to conventional means such as a heater 30 and a cooling zone 35. The twist set yarn then passes through twist zone 50 and through the downstream portion of charge zone 40 where the charge on the filaments is dissipated. Feed means 60 and 70 and heater 65 may be conventionally employed downstream of twist zone 60 to control the characteristics of the false twisted yarn, if desired.

Having described the present invention in detail, it is obvious that one skilled in the art will be able to make variations and modifications thereto without departing from the scope of the invention. Accordingly, the scope of the present invention should be determined only by the claims appended thereto.

What is claimed is:

1. A method of applying false twist to a multistrand textile material comprising the steps of:

a. feeding said material under controlled tension conditions to a charge zone;

b. applying sufficient charge density to said strands to cause said strands to repel each other;

e. passing said material into a twist zone, said zone having a plurality of electrodes spaced around the inner periphery thereof; said electrodes being electrically associated in pairs, said material assuming a flared condition within said twist zone;

d. creating a maximum voltage potential across two of said electrodes on oppostie sides of said zone, one of said electrodes having an opposite polarity to said strands and one of said electrodes having a like polarity of said strands, whereby said flared strands are attracted toward said electrodes having said opposite polarity; and

e. sequentially shifting the phase angle of said voltage to shift said maximum potential from electrode pair to electrode pair, said attracted strands following said maximum potential to impart twist to said material.

2. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein said textile material is a multifilament thermoplastic yarn.

3. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein further,

. said twist is set in said material upstream of said twist 7. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein the magnitude of the voltage at each electrode pair is substantially equal.

8. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein said phase angle of said voltage is shifted by a capacitor-resistor circuit.

9. A twist means for imparting false twist to a multistrand textile material comprising:

a. a twist zone chamber, said chamber defining a passageway therethrough, said chamber having a plurality of electrodes disposed thereabout, said electrodes defining a closed path around said passagey;

b. electrical means associating one of said electrodes with another of said electrodes whereby a voltage potential can be created thereacross, said electrical means further uniting said pairs of electrodes to create an electrical closed path therearound;

c. voltage supply means for said electrodes; and

d. means for creating maximum voltage potential across one pair of electrodes and shifting maximum voltage potential from one electrode pair to an adjacent electrode pair around the closed path created by said electrodes.

10. A twist means as defined in claim 9 wherein said chamber has an entrance and an exit at opposite ends thereof, said entrance and said exit having restrictor means associated therewith.

1 1. A twist means as defined in claim 10 wherein said chamber is further operatively associated with atmosphere control means.

12. A twist means as defined in claim 9 wherein said means for creating voltage potential and shifting maximum voltage potential from electrode pair to electrode pair comprises a circuit having an amplifying means and a transformer for each electrode pair, said amplifying means being electrically associated, and having a phase shifting circuit therebetween and forming a part of an oscillator.

13. A twist means as defined in claim 12 wherein said phase shift circuit is a capacitor-resistor circuit.

14. A rotating alternating current field device comprising:

a. a plurality of pairs of electrodes, said pairs of electrodes being electrically associated to define an electrical closed path;

b. an amplifying means and a transformer electrically associated with each pair of electrodes, one of said amplifying means being an inverter-amplifier;

c. voltage phase shifting means connecting each amplifying means with an adjacent amplifying means; and

d. a source of direct current voltage for said system.

13 14 15. A rotating alternatingcurrent fielddevice as denating current voltage; fined in claim 14 wherein said phase shifting means is e. means for supplying alternating current voltage to a capacitor-resistor circuit. a pair of electrodes to create a voltage potential 16. A rotating alternating current field comprising: thereacross; and a.- a plurality of electrodes; f. means to successively shift said voltage potential b. electrical means associating said electrodes in indifrom electrode pair to electrode pair around said vidual pairs and associating said pairs to define an closed path, whereby a maximum voltage potential electrical closed path; occurs across one pair of electrodes only at any one c. a source of direct current voltage; time voltage is supplied to said field. d. an oscillator for converting said voltage to alter- 4 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pa 3,775,959 Dated December 4, 1973 Invento James R. Bond It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Delete Claims 14 through 16.

Signed and sealed this 23rd day of July 1971,.

(SEAL) Attest:

MCCOY M; GIBSON, JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents ORM Ponoso (10-69) USCOMM-DC 60376-P69 Q U.S. GOVERNMENT PRINTING OFFICE: I. 0-366-334. 

1. A method of applying false twist to a multistrand textile material comprising the steps of: a. feeding said material under controlled tension conditions to a charge zone; b. applying sufficient charge density to said strands to cause said strands to repel each other; c. passing said material into a twist zone, said zone having a plurality of electrodes spaced around the inner periphery thereof; said electrodes being electrically associated in pairs, said material assuming a flared condition within said twist zone; d. creating a maximum voltage potential across two of said electrodes on oppostie sides of said zone, one of said electrodes having an opposite polarity to said strands and one of said electrodes having a like polarity of said strands, whereby said flared strands are attracted toward said electrodes having said opposite polarity; and e. sequentially shifting the phase angle of said voltage to shift said maximum potential from electrode pair to electrode pair, said attracted strands following said maximum potential to impart twist to said material.
 2. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein said textile material is a multifilament thermoplastic yarn.
 3. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein further, said twist is set in said material upstream of said twist zone.
 4. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein said strands are charged adjacent said twist zone.
 5. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein said voltage is operating in a frequency range of from about 25 KHz to about 90 KHz.
 6. A method of applying false twist to a multistraNd textile material as defined in claim 1 wherein said charge on said strands are in the range of from about 5000 volts to about 100, 000 volts.
 7. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein the magnitude of the voltage at each electrode pair is substantially equal.
 8. A method of applying false twist to a multistrand textile material as defined in claim 1 wherein said phase angle of said voltage is shifted by a capacitor-resistor circuit.
 9. A twist means for imparting false twist to a multistrand textile material comprising: a. a twist zone chamber, said chamber defining a passageway therethrough, said chamber having a plurality of electrodes disposed thereabout, said electrodes defining a closed path around said passageway; b. electrical means associating one of said electrodes with another of said electrodes whereby a voltage potential can be created thereacross, said electrical means further uniting said pairs of electrodes to create an electrical closed path therearound; c. voltage supply means for said electrodes; and d. means for creating maximum voltage potential across one pair of electrodes and shifting maximum voltage potential from one electrode pair to an adjacent electrode pair around the closed path created by said electrodes.
 10. A twist means as defined in claim 9 wherein said chamber has an entrance and an exit at opposite ends thereof, said entrance and said exit having restrictor means associated therewith.
 11. A twist means as defined in claim 10 wherein said chamber is further operatively associated with atmosphere control means.
 12. A twist means as defined in claim 9 wherein said means for creating voltage potential and shifting maximum voltage potential from electrode pair to electrode pair comprises a circuit having an amplifying means and a transformer for each electrode pair, said amplifying means being electrically associated, and having a phase shifting circuit therebetween and forming a part of an oscillator.
 13. A twist means as defined in claim 12 wherein said phase shift circuit is a capacitor-resistor circuit.
 14. A rotating alternating current field device comprising: a. a plurality of pairs of electrodes, said pairs of electrodes being electrically associated to define an electrical closed path; b. an amplifying means and a transformer electrically associated with each pair of electrodes, one of said amplifying means being an inverter-amplifier; c. voltage phase shifting means connecting each amplifying means with an adjacent amplifying means; and d. a source of direct current voltage for said system.
 15. A rotating alternating current field device as defined in claim 14 wherein said phase shifting means is a capacitor-resistor circuit.
 16. A rotating alternating current field comprising: a. a plurality of electrodes; b. electrical means associating said electrodes in individual pairs and associating said pairs to define an electrical closed path; c. a source of direct current voltage; d. an oscillator for converting said voltage to alternating current voltage; e. means for supplying alternating current voltage to a pair of electrodes to create a voltage potential thereacross; and f. means to successively shift said voltage potential from electrode pair to electrode pair around said closed path, whereby a maximum voltage potential occurs across one pair of electrodes only at any one time voltage is supplied to said field. 